Cable fairlead assembly

ABSTRACT

Cable fairlead assembly including an outer, retainer, sleeve element and an inner, diametrically divided, grommet element comprising two symmetrical tubular halves secured in position by the retainer to provide a cable passageway. The retainer element is a longitudinally slotted sleeve having a shaped outer surface to permit installation from either side of, and retention in, a panel hole of predetermined size. The inner surface of the retainer is shaped to accept and secure the two grommet halves in position when installed in the retainer from either end thereof.

United States Patent Mason May 30, 1972 [541 CABLE FAIRLEAD ASSEMBLY2,787,486 4 1957 Thiry ..16/2 3 056 852 10/1962 Sachs ..l6/2 x 72 I t Krt E. M F 1 1 Cahf 3,076,668 2/1963 Famely ..248/56 x [73] Assignee:McDonnell Douglas Corporation [22] Filed: g 5 1970 PrimaryExaminer-Bobby R. Gay

App]. No.: 61,053

[52] US. Cl ..16/2, 248/56, 285/159 [51] Int. Cl ..Fl6l5/00 [58] Fieldof Search ..l6/2, 108, 109; 248/56; 285/159 [56] References Cited UNITEDSTATES PATENTS 2,418,105 3/1947 Wohler ..16/2 X Assistant Examiner-PeterA. Aschenbrenner AttarneyWalter J. Jason, Donald L. Royer and D. N. .leu

[ 5 7] ABSTRACT Cable fairlead assembly including an outer, retainer,sleeve element and an inner, diametrically divided, grommet elementcomprising two symmetrical tubular halves secured in position by theretainer to provide a cable passageway. The retainer element is alongitudinally slotted sleeve having a shaped outer surface to permitinstallation from either side of, and retention in, a panel hole ofpredetermined size. The inner surface of the retainer is shaped toaccept and secure the two grommet halves in position when installed inthe retainer from either end thereof.

8 (Ilaims, 6 Drawing Figures CABLE FAIRLEAD ASSEMBLY BACKGROUND OF THEINVENTION 7 My present invention pertains generally to the field ofcontrol cable fairleads and more particularly to a cable fairleadassembly which provides exceptionally low frictional support andguidance for a moving cable.

Aircraft fairleads presently used for support and guidance of movingcontrol cables are normally fabricated by injection molding processes.The materials which can be used in such processes, however, producefairleads that have a certain amount of friction on the-moving controlcables supported and guided by them. While the amount of frictionencountered is relatively small, there are instances in which it isdesirable or necessary to reduce the friction produced by injectionmolded fairleads on their respective cables. Furthermore, the very lowfriction fairlead should be easily mounted on, or removed from, acontrol cable and also be easily in-- stalled in, or removed from, asupporting panel hole. It is also advantageous and sometimes necessaryto have a low friction fairlead which can be readily and securelyinstalled in a panel hole from either side of the panel.

SUMMARY OF THE INVENTION Briefly, and in general terms, my invention ispreferably accomplished by providing a cable fairlead assembly includingan outer, retainer, sleeve element made of a relatively stiff (andmoldable) material such as a suitable polyarnide (nylon) and an inner,diametrically divided, grommet element made of a very low-friction (andmachinable) material such as graphite-filled polytetrafluoroethylene.The grommet element comprises two identical tubular halves symmetricallyarranged and secured in position as a unit by the retainer to provide asupport and guide for a cable.

The retainer element is a longitudinally slotted sleeve having a shapedouter surface to permit installation from either side of, and retentionin, a panel hole of predetermined size. The inner surface of theretainer is shaped to accept and secure the two grommet halves firmly inposition when installed in the retainer from either end thereof. Theouter surfaces of the grommet halves include a detent structure forengaging either of the complementary structures defining twolongitudinally spaced channels or grooves in the inner surface of theretainer. The inner surfaces of the grommet halves are suitably shapedto form the cable passageway when the grommet halves are installed inthe retainer.

BRIEF DESCRIPTION OF THE DRAWING My invention will be more fullyunderstood, and other features and advantages thereof will becomeapparent, from the following description of an exemplary embodiment ofthe invention. The description is to be taken in conjunction with theaccompanying drawing, in which:

FIG. 1 is a side elevational view of the retainer element of a cablefairlead assembly constructed according to this inventron;

FIG. 2 is a sectional view of the retainer as taken along the line 22indicated in FIG. 1;

FIG. 3 is a side elevational view of one tubular half of thediametrically divided grommet element of the cable fairlead assembly;

FIG. 4 is a front elevational view of the tubular half of the grommetelement as taken along the line 44 indicated in FIG. 3;

FIG. 5 is a side elevational view of the cable fairlead assembly; and

FIG. 6 is a sectional view of the cable fairlead assembly as taken alongthe line 66 indicated in FIG. 5.

' DESCRIPTION OF THE PRESENT EMBODIMENT FIG. I is a side elevationalview of the outer, retainer, sleeve element 10 of my cable fairleadassembly. The retainer element 10 is generally a cylindrical sleeveincluding a longitudinal gap or slot 12 which is preferably of uniformwidth A. The retainer 10 has a minimum inner diameter B and a maximumouter diameter C as indicated in FIG. 1. The retainer 10 is preferablyinjection molded from a suitable polyamide compound material such asnylon which produces a fairly stiff (low flexibility) article.

FIG. 2 is a sectional view of the retainer '10 as taken along the line2--2 indicated in FIG. 1. It can be seen that the retainer 10 islongitudinally symmetrical with respect to a plane perpendicular to itsaxis at the axial midpoint of the retainer. The cylindrical innersurface 14 is contoured or shaped at its ends to provide inwardlybeveled surfaces 16 and 18, and rectangular cross sectional channels 20and 22 located respectively adjacent longitudinally to the beveledsurfaces. Each of the beveled surfaces 16 and 18 intersect in a centralangle D, and the channels 20 and 22 each has a diameter E and axiallength F. In the channels 20 and 22, the channel sides nearest to theirrespective ends of the retainer 10 are each located a distance G fromthe surfaces of such ends. The longitudinally spaced channels or annulargrooves 20 and 22 are defined by respective complementary structures orcatch means which can be selectively engaged by a detent structureprovided on the outer surface of a grommet element to be described indetail later.

The cylindrical outer surface 24 of the retainer 10 is also contoured orshaped at its ends to provide left and right cylindrical surfaces 26 and28 each having a diameter H and an axial length I. A rectangular crosssectional channel 30 is formed in the longitudinally central portion ofthe outer surface 24 and has a diameter J and an axial length K. Thecylindrical rim surfaces 32 and 34 adjacent to the left and right edgesof the central channel 30 are respectively connected to the end surfaces26 and 28 with outwardly flared or beveled surfaces 36 and 38. Each ofthe rim surfaces 32 and 34 has the maximum diameter C, and the beveledsurfaces 36 and 38 are each beveled at an angle L measured from a planeperpen dicular to the axis of retainer 10. The retainer 10 has anoverall length M.

FIG. 3 is a side elevational view of one tubular half 40 of a grommetelement 42 which is formed with another identical tubular half 44(simply indicated in phantom lines) held in diametrical face contact bythe retainer 10. The grommet half 40 has a minimum inner diameter N anda maximum outer diameter 0 which is actually that of an annular ridge ordetent structure 46. The major portion of the outer surface 48 of thegrommet half 40 has a diameter P. The grommet half 40 is preferablymachined from a rod of, for example, graphitefilledpolytetrafluoroethylene which produces a very low-friction article.

FIG. 4 is a front elevational view of the grommet half 40 as taken alongthe line 44 indicated in FIG. 3. The cylindrical inner surface 50 iscontoured or shaped at its ends to provide outwardly beveled surfaces 52and 54. The surfaces 52 and 54 each has an axial length Q, and isbeveled at an angle R measured with respect to the axis of the grommethalf 40. It should be noted that where the grommet half 40 is relativelylarge, the beveled surfaces 52 and 54 are joined to their respectiveends of the inner surface 50 by suitably curved surfaces so as to avoidany sharp comers at the surface junctions; that is, fully rounded comersmay be necessary under certain conditions. The grommet halves 40 and 42form a cable passageway 56 when held in diametrical face contact by theretainer 10.

The cylindrical outer surface 58 of the grommet half 40 has beencontoured or shaped to provide cylindrical surfaces 48a and 48brespectively left and right of the detent structure 46, as shown in FIG.4. The cylindrical surface 58 of detent struc ture 46 has the diameter0, and the cylindrical surfaces 48a and 48b each-has the diameter P, asindicated in FIG. 3. The cylindrical detent surface 58 has an axiallength S, and the left edge of such detent surface is located a distanceT from the left end of the grommet half 40. The left and right surfaces480 and 48b are connected to the detent surface 58 by outwardly beveledsurfaces 60 and 62 each of which makes an angle U measured with respectto a plane perpendicular to the axis of the grommet half 40. The beveledsurfaces 60 and 62 are preferably joined in small radii (0.01 inch inthe following exemplary embodiment) junctions with the surfaces 48a and48b, respectively.

The right end of the cylindrical surface 48b can be chamfered at anangle of 45 across an axial length of 0.02 inch, for example, in theexemplary embodiment of this invention having the following nominal ormean dimensional values as referred to FIGS. I through 4. A 0.2 inch, B0.442 inch, C 0.56 inch, D 60, E =0.49 inch, F 0.06 inch, G 0.046 inch,H 0.54 inch, I= 0.106 inch, .1 0.498 inch, K 0.13 inch, L 75, M 0.5inch, N 0.22 inch, 0.48 inch, P 0.438 inch, Q 0.03 inch, R 45, S 0.03inch. T 0.08 inch, and U 45. The grommet half 44 can, of course, besubstantially identical to the grommet half 40. The foregoingdimensions, and other dimensions or types of materials noted herein, ofthe cable fairlead assembly or its components are merely illustrativeexamples of the exemplary embodiment thereof and are not intended tolimit the scope of my invention in any manner.

FIG. 5 is a side elevational view of the cable fairlead assembly 64including the grommet halves 40 and 44 secured in diametrical facecontact as a unitary grommet element 42 by the retainer element 10. Theretained grommet halves 40 and 44 are not to have a separation betweentheir contacting faces greater than a dimension V which is equal to, forexample, 0.01 inch in the exemplary embodiment given above. The cablepassageway 56 of the grommet element 42 is used for a control cable 66indicated in phantom lines in FIG. 4. The cable fairlead assembly 64, inthis instance, is preferably used for a straight run of a A: inchdiameter, l X I9 control cable 66, for example. The diameter of thecable passageway 56 can be made somewhat smaller than proportionatelyindicated in FIG. 4; however, the indicated larger diameter allows asmall but reasonable amount of cable angle to exist relative to the axisof the passageway (an angled run) without binding in an ordinarilystraight run.

FIG. 6 is a sectional and front elevational view of the cable fairleadassembly 64 as taken along the line 6-6 indicated in FIG. 5. Theassembly 64 is shown installed in a panel hole 68 of panel 70 which isindicated sectionally in phantom lines. The panel hole 68 has a diameterW which can be equal to one-half inch for the exemplary embodiment ofthis invention given previously above. It can be seen from this figurethat the right end of the grommet element 42 protrudes or extends anaxial distance X beyond the corresponding end of its retainer 10. Again,for the exemplary embodiment given above, X 0.04 inch, for example.

The panel 70 has a thickness Y which is preferably oneeighth inch forthe retainer channel 30 having an axial length K of 0. 13 inch. Theaxial length K of the retainer channel 30 is preferably about equal tothe panel thickness Y which is preferably about one-quarter the overalllength M of the retainer 10 and/or is sufficiently thick to support thecable fairlead assembly 64 firmly and rigidly. The thickness Y of thepanel 70 (and channel 30 axial length K), however, should not be anexcessively large fraction of the retainer 10 overall length M, for easeof installation and assembly of the fairlead assembly 64 in the panelhole 68. Each of the grommet halves 40 and 44 has an overall length Z(FIG. 4) which is, of course, equal to the sum of the retainer length M(FIG. 2) and the grommet protrusion distance X (FIG. 6). Thus, in theexemplary embodiment given above, Z 0.54 inch, for example.

Installation and assembly of the cable fairlead assembly 64 in the panelhole 68 can be accomplished by first passing the control cable 66 (FIG.4) running in the panel hole through the retainer slot 12 (FIG. I) andinto the retainer 10. The retainer 10 is then pressed into the panelhole 68 as shown in FIG. 6. Next, the grommet halves 40 and 44 aresnapped into the panel-mounted retainer 10 about the cable 66 with thediametrically contacting faces of the grommet halves oriented generallyat right angles to a diametrical axial plane bisecting the unifonn widthA of the slot 12 as illustrated in FIG. 5.

The grommet halves 40 and 44 can be inserted into the panel-mountedretainer 10 shown in FIG. 6 from either side of the panel 70. Thechamfered ends of the grommet halves 40 and 44 are inserted into theretainer 10 until the detent structure 46 snaps into its complementarychannel or groove 20 (or 22 if inserted from the right side of panel70). Note that retainer slot 12 and the longitudinal locations of thechannels 20 and 22 near respective ends of the retainer 10 permit readyflexing (raising) of the annular lips before their correspondingchannels and, hence, easy installation of the grommet halves 40 and 44in the panel-mounted retainer. The longitudinal slot 12 in the retainer10 is also needed to allow the retainer to be easily installed in thepanel hole 68. Conversely, the grommet halves 40 and 44 and retainer 10can be easily removed from the panel hole 68 because of the retainerslot 12 and the longitudinal end locations of the channels 20 and 22.However, this cannot be accomplished quite as readily as installation.

It is to be understood that the exemplary embodiment of this inventionas described above and shown in the accompanying drawing is merelyillustrative of, and not restrictive on, the broad invention and that Ido not desire to be limited in my invention to the exact details ofconstruction or arrangement shown and described, since obviousmodifications will occur to persons skilled in the art.

I claim:

1. Fairlead assembly for providing support and guidance to a cablepassing therethrough, said assembly comprising:

a retainer element including an outer sleeve;

a grommet element including separate inner tubular sections retained ina unitary arrangement by said sleeve whereby a passageway for said cableis obtained; and

means for securing said retainer and grommet elements in predetermined,axially fixed, positions relative to each other, said securing meansincluding a detent means on said grommet element, and a complementarycatch means on said retainer element for engaging said detent means andwherein said detent means includes at least a circumferential portion ofan annular ridge located near a longitudinal end of said grommetelement, and said complementary catch means includes at least acircumferential portion of structure defining an internal annularchannel located near a corresponding longitudinal end of said retainerelement.

2. The invention as defined in claim 1 wherein said complementary catchmeans further includes at least a circumferential portion of structuredefining another internal annular channel located near the otherlongitudinal end of said retainer element whereby said grommet elementcan be installed in said retainer element from either end thereof.

3. The invention as defined in claim I wherein said sleeve includes alongitudinal slot therein.

4. The invention as defined in claim 3 wherein said sleeve includesmeans for attaching it to relatively fixed structure.

5. The invention as defined in claim 4 wherein said attaching meansincludes circumferential structure defining an external annular channelin said sleeve, and said relatively fixed structure includes a panelportion having circumferential structure defining a predetermined sizehole therein, said external channel defining structure being providedfor normally engaging said hole defining structure and firmly mountingsaid sleeve to said relatively fixed structure.

6. Fairlead assembly for providing support and guidance to a cablepassing therethrough, said assembly comprising:

a retainer element including an outer sleeve, said sleeve including alongitudinal slot therein and means for attaching it to relatively fixedstructure, said attaching means including circumferential structuredefining an external annular channel in said sleeve, and said relativelyfixed structure including a panel portion having circumferentialstructure defining a predetermined size hole therein, said externalchannel defining structure being provided for normally engaging saidhole defining structure and firmly mounting said sleeve to saidrelatively fixed structure;

a grommet element including inner tubular sections retained in a unitaryarrangement by said sleeve whereby a passageway for said cable isobtained, said tubular sections comprising two substantially identicaldiametrically divided halves of said grommet element; and

means for-securing said retainer and grommet elements in predetermined,axially fixed, positions relative to each other, said securing meanscomprising a detent means on said grommet element and a complementarycatch means on said retainer element for engaging said detent means,said detent means including at least a circumferential portion of anannular ridge located near a longitudinal end of said grommet element,and said complementary catch means including at least a circumferentialportion of structure defining an internal annular channel located near acorresponding longitudinal end of said retainer element.

7. The invention as defined in claim 6 wherein said retainer element isfabricated of relatively stiff material, and said grommet element isfabricated of extremely stiff and very low friction material.

8. The invention as defined in claim 6 wherein said external channel iscentrally located longitudinally on said sleeve, and said complementarycatch means further includes at least a circumferential portion ofstructure defining another internal annular channel located near theother longitudinal end of said retainer element.

1. Fairlead assembly for providing support and guidance to a cablepassing therethrough, said assembly comprising: a retainer elementincluding an outer sleeve; a grommet element including separate innertubular sections retained in a unitary arrangement by said sleevewhereby a passageway for said cable is obtained; and means for securingsaid retainer and grommet elements in predetermined, axially fixed,positions relative to each other, said securing means including a detentmeanS on said grommet element, and a complementary catch means on saidretainer element for engaging said detent means and wherein said detentmeans includes at least a circumferential portion of an annular ridgelocated near a longitudinal end of said grommet element, and saidcomplementary catch means includes at least a circumferential portion ofstructure defining an internal annular channel located near acorresponding longitudinal end of said retainer element.
 2. Theinvention as defined in claim 1 wherein said complementary catch meansfurther includes at least a circumferential portion of structuredefining another internal annular channel located near the otherlongitudinal end of said retainer element whereby said grommet elementcan be installed in said retainer element from either end thereof. 3.The invention as defined in claim 1 wherein said sleeve includes alongitudinal slot therein.
 4. The invention as defined in claim 3wherein said sleeve includes means for attaching it to relatively fixedstructure.
 5. The invention as defined in claim 4 wherein said attachingmeans includes circumferential structure defining an external annularchannel in said sleeve, and said relatively fixed structure includes apanel portion having circumferential structure defining a predeterminedsize hole therein, said external channel defining structure beingprovided for normally engaging said hole defining structure and firmlymounting said sleeve to said relatively fixed structure.
 6. Fairleadassembly for providing support and guidance to a cable passingtherethrough, said assembly comprising: a retainer element including anouter sleeve, said sleeve including a longitudinal slot therein andmeans for attaching it to relatively fixed structure, said attachingmeans including circumferential structure defining an external annularchannel in said sleeve, and said relatively fixed structure including apanel portion having circumferential structure defining a predeterminedsize hole therein, said external channel defining structure beingprovided for normally engaging said hole defining structure and firmlymounting said sleeve to said relatively fixed structure; a grommetelement including inner tubular sections retained in a unitaryarrangement by said sleeve whereby a passageway for said cable isobtained, said tubular sections comprising two substantially identicaldiametrically divided halves of said grommet element; and means forsecuring said retainer and grommet elements in predetermined, axiallyfixed, positions relative to each other, said securing means comprisinga detent means on said grommet element and a complementary catch meanson said retainer element for engaging said detent means, said detentmeans including at least a circumferential portion of an annular ridgelocated near a longitudinal end of said grommet element, and saidcomplementary catch means including at least a circumferential portionof structure defining an internal annular channel located near acorresponding longitudinal end of said retainer element.
 7. Theinvention as defined in claim 6 wherein said retainer element isfabricated of relatively stiff material, and said grommet element isfabricated of extremely stiff and very low friction material.
 8. Theinvention as defined in claim 6 wherein said external channel iscentrally located longitudinally on said sleeve, and said complementarycatch means further includes at least a circumferential portion ofstructure defining another internal annular channel located near theother longitudinal end of said retainer element.